HEARING AID SYSTEM COMPRISING A DATABASE OF ACOUSTIC TRANSFER FUNCTIONS

A hearing aid system comprises a hearing aid configured to be worn on the head at or in an ear of a user. The hearing aid comprises a microphone system comprising a multitude of M of microphones arranged in said hearing aid and adapted to provide M corresponding electric input signals xm(n), m=1, . . . , M, n representing time. The environment sound at a given microphone comprises a mixture of a) a target sound signal sm(n) propagated via an acoustic propagation channel from a direction to or a location (θ) of a target sound source to the mth microphone of the hearing aid when worn by the user, and b) possible additive noise signals vm(n) as present at the location of the mth microphone, wherein the acoustic propagation channel is modeled as xm(n)=sm(n)hm(θ)+vm(n), and wherein hm(θ) is an acoustic impulse response for sound for that acoustic propagation channel. The hearing aid system comprises A) a processor connected to said number of microphones, and B) a database Θ comprising a multitude of dictionaries Δp, p=1, . . . , P, where p is a person index, of vectors, termed ATF-vectors, whose elements ATFm, m=1, . . . , M, are frequency dependent acoustic transfer functions representing direction- or location-dependent (θ), and frequency dependent (k) propagation of sound from a direction or location (θ) of a target sound source to each of said M microphones, k being a frequency index, k=1, . . . , K, where K is a number of frequency bands, when said microphone system is mounted on a head at or in an ear of a natural or artificial person (p′), and wherein each of said dictionaries Δp comprises ATF-vectors for a given person (p) for a multitude of different directions or locations θj, j=1, . . . , J, relative to the microphone system. The processor is configured to, at least in a learning mode of operation, determine personalized ATF-vectors (ATF*) for said user based on said multitude of dictionaries Δp of said database Θ, said electric input signals xm(n), m=1, . . . , M, and said model of the acoustic propagation channels. The invention may e.g. be used in beamforming, own voice estimation, own voice detection, keyword detection, etc.